Cold hardiness & minimum temperature

Is Angel's Trumpet (Brugmansia suaveolens)cold hardy? Hardiness zone & min temp

Also called Angel's trumpet, Snowy angel's trumpet, Angel's tears.

More about angel's trumpet

About Angel's Trumpet

Brugmansia suaveolens · also called Angel's trumpet, Snowy angel's trumpet · flowering

Angel's trumpet is a fast-growing tropical shrub or small tree prized for huge, pendulous, intensely fragrant trumpet flowers. Give it full sun, rich moist soil, generous feeding, and protection below 10C. Every part is highly poisonous (tropane alkaloids), so the ASPCA and Pet Poison Helpline rate it toxic to pets and people.

Cold limit: USDA 9-11 (root-hardy to ~7b-8 with heavy mulch/protection; grown as a container or overwintered plant elsewhere) (15-30C ideal; keep above 7-10C)

Watch for — Spider mites: Common indoors and in dry air, especially over winter. Look for fine webbing, stippling, and yellowing on leaf undersides; treat with insecticidal soap or neem and raise humidity. Breaking the cycle takes 3-4 weeks of repeat treatment.

What angel's trumpet's hardiness rating actually means

Angel's Trumpet is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Its RHS rating of H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 9-11 (root-hardy to ~7b-8 with heavy mulch/protection; grown as a container or overwintered plant elsewhere) — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Angel's Trumpet shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for angel's trumpet as it gets too cold:

Down to roughly about 1 to 5 °C it copes, especially if dry and sheltered.
A sustained hard frost collapses the top growth; whether it returns depends on whether the roots, crown or tubers froze.
Wet cold is far more lethal than dry cold for this plant — soggy, frozen soil is the usual killer.

Can angel's trumpet go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (root-hardy to ~7b-8 with heavy mulch/protection; grown as a container or overwintered plant elsewhere) or a frost-free UK microclimate.
In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter.
A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when angel's trumpet can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline angel's trumpet

Angel's Trumpet is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost.
Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse.
Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones.
Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.

Angel's Trumpet hardiness — frequently asked questions

Is angel's trumpet cold hardy?

Angel's Trumpet is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Borderline outdoors. In its mild end of USDA 9-11 (root-hardy to ~7b-8 with heavy mulch/protection; grown as a container or overwintered plant elsewhere) (and sheltered UK gardens) angel's trumpet can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature angel's trumpet can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Angel's Trumpet shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is angel's trumpet?

Angel's Trumpet is rated USDA 9-11 (root-hardy to ~7b-8 with heavy mulch/protection; grown as a container or overwintered plant elsewhere) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can angel's trumpet survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 (root-hardy to ~7b-8 with heavy mulch/protection; grown as a container or overwintered plant elsewhere) or a frost-free UK microclimate. In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter. A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

How do I protect angel's trumpet from frost?

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost. Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse. Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones. Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.